1. Field of the Invention
The present invention relates to an electrophotographic photosensitive member, and more particularly to an electrophotographic photosensitive member comprising a photosensitive layer containing a disazo pigment having a specific structure, and to a process cartridge and an electrophotographic apparatus having the electrophotographic photosensitive member.
2. Related Background Art
Electrophotographic photosensitive members having an organic photoconductive materials have advantages in that their productivity is satisfactory, their cost can be reduced relatively and their color sensitivity can desirably be controlled by adequately selecting the pigment or dye used. Therefore, various studies of such electrophotographic photosensitive members has been carried out. In particular, a function-separated-type photosensitive member has been developed by which poor sensitivity and unsatisfactory durability that have been experienced with the conventional organic electrophotographic photosensitive member can be overcome. The foregoing function-separated-type photosensitive member has a charge generating layer which contains charge generating materials, such as an organic photoconductive pigment and dye, and a charge transporting layer which contains charge transporting materials, such as photoconductive polymers and low-molecular weight organic photoconductive materials.
The azo pigments have, among the organic photoconductive materials, excellent photoconductivity and various kinds of them can be relatively easily obtained by combining amine components and coupler components. Therefore, various pigments have been disclosed, for example, in Japanese Patent Laid-Open No. 56-116040, Japanese Patent Laid-Open No. 61-231052, Japanese Patent Laid-Open No. 62-267363, and Japanese Patent Laid-Open No. 63-264762.
In recent years, however, there have been demands for higher image quality and more excellent durability. To meet these demands, electrophotographic photosensitive members having higher sensitivity, more excellent electrophotographic characteristics, even when repeatedly used and having excellent environment stability have been desired.